HBACTION-INTK.NMIIKS \\nii KAC II At.l.M \\D REAGENT. 



l.'.l 



reactivities with chrumi.- avid an- moderate and thote 



with pyrogallic acid very low; while the corresponding 



reactivities with //. mtniceui are high and very high, 



The chromic-acid reaction U an much 



ii r than the pyrogallie-acid reaction in //. kaiherintr 



i- !,.. T in //. ['uniceus. Thi* interesting inver- 



intensities of the two starches with these 



reap nsi.-ti-nt with well-separated < Iwnuters of 



:es. as already pointed oat 1 n ( 'rinum the two 



-ie are much more reactive to chromic acid 



. whereas the reverse relationship 



.-i in th< <>f the tender species; moreover, 

 > ur.. .iti.T are inverted in comparison with the 

 f,.rni. r. In V.nnr the chromic-acid reactions are mod- 

 erate, while those of pyrogallic acid are so very low as to 

 be almost absolutely negligible, making a very marked 

 difference between the reaction-intensitiec. In Narcistiu 



hroraic-acid r< a. tion is moderate and the pyrogallic- 

 acid reaction low, but without much difference between 

 them. In I. ilium all of the reactions are high to very high, 

 the chromic-acid reactions being the higher except in one 

 species, in which both reactions are the same, although 

 during the earlier part of the experiments chromic acid 

 howed a somewhat higher reactive intensity than 

 I'vrogallic acid. 



The degree of separation of the two curves in the 

 other three specimens is not alike in any two. In Iris 

 .ii-- < -hromic -acid reactions are high in all four starches, 

 and the pyrngallic-acid reactions moderate in two, low 

 in one, ainl MTV high in one. The distance between the 



; is marked in all four, and in /. pertica var. 

 purpurta the curves are inverted in other words, the 

 first three starches are more sensitive to chromic acid than 



rogallic acid, while in tin- last there is the reverse. 

 ut this group of charts it will be seen that this 

 . of Iris exhibit* a number of peculiarities of reac- 

 tivity which definitely differentiate it from the preceding 

 . which in turn seem to be closely related in 

 their reactivities. Inversion and reversion of the curves 

 of the irids corresponding to the foregoing will be found 



arts B 7, B 8, B 9, B 10, B 12, B 22, and B 36. In 



"lus and Tritonia the chromic-acid reactions are 

 high and the pyrogallic-acid reactions moderate, the 

 reactions of the two starches with each reagent being 

 the same or practically the same, but the reaction-intensi- 

 ties with the two reagents being markedly different In 



ia the chromic-acid and pyrogallic-acid reactions 

 are distinctly higher in Begonia tingle crimson scarlet 

 than in If. tocotrana, and the difference between the two 

 reactions is very much greater in the latter than in the 



r. In Phaitu and ililtonia the chromic-acid reac- 

 tions are much higher than the pyrogallic-acid reactions, 

 hut the amount of separation between the two carves is 

 nearly the same. 



Examining this chart (B31) from the aspect of 

 generic and subgeneric differentiation, it is essential 

 to bear in mind that certain genera are represented by 

 individuals that show such marked differences as to 

 indicate that they belong to subgenera or some other 

 form of subgeneric division, as in Hamanthut, Cn'num, 

 Iris, and Begonia, and that on this account variations of 

 their curves may be such as to appear to be opposed to 

 recognized generic grouping. With this peculiarity in 



view, beginning with Amaryllis and firururtyui (.losely 

 related genera), it will be seen the positions of the two 

 curves in each are very different in Amaryllis the two 

 curves are well separated, but in Hruntriyia they are 

 the same. There is here a definite separation of the two 

 genera. These genera are well separated from Hippeas- 

 Irum, and the latter from the H<rmanthiu, by the marked 

 differences in the curve*. In the three forms of Jlip- 

 peaatrum the chr<>iiuc-acid curve is higher or eu-n much 

 higher than in the preceding and succeeding genera, and 

 it is in two well above and in one definitely iiUnc the 

 pyrogallic-acid curve. The pictures presented by the 

 curves in these three generic groups are so different that 

 one could not possibly be confounded with another. In 

 Httmanthtu there is a drop of the chromic-acid carve 

 in //. leaiherina and //. punicetu; and a very marked 

 drop of the pyrogallic-acid curve in the former, but a 

 marked rise in the latter, giving rise to a well-defined 

 separation of this genus from Ilijipeastrum and to inver- 

 sion of the curves in //. puniceus with consequent separa- 

 tion of the two species. In Crinum the picture is again 

 different, there being a rise of the chromic-acid curvi- 

 accompanied by a rue of the pyrogallic-acid curve in 

 two and a fall in one. 



Inversion of the curves occurs in relation to C. tey- 

 lanicum, this feature of itself differentiating this tender 

 species from the two hardy species. In K trine the pic- 

 ture is again and markedly altered. Hoth curves fall, 

 the chromic-acid curve to a moderate level and the pyro- 

 gallic-acid curve almost to zero, and with very little or 

 practically no difference in the reactivities of the four 

 starches with each of the reagents. In Narcissus, while 

 the chromic-acid carve remains at practically the same 

 level as in Nerine the pyrogallic-acid curve has ruun 

 almost to the level of moderate reactivity, thus causing 

 some separation of the two curves and giving a generic 

 combination of the two curves which differs from that 

 found in any other part of the chart. In Lilium the 

 picture is again changed and is again distinctive of the 

 genus. And so on, as we pass to Iris, Oladioltu and 

 Tritonia, Begonia, Phaitu, and Millonin, the curves vary 

 in their positions and degree of separation in such man- 

 ners as to differentiate or suggest, as the case may be, 

 not only generic but subgeneric groups. The Oladioltu 

 and Tritonia curves are practically identical, the explana- 

 tion for which has been referred to repeatedly. The 

 first three and the last of the Iris are well separated; 

 but Begonia shows curves of the two starches which, 

 while well separated, rather indicate well-separated spe- 

 cies than representatives of subgenera, as in the case of 

 many of the other charts. 



While it is true that in a number of instances a genu* 

 is represented by only a single species and that, inasmuch 

 as the reactivities of different species of a genus exhibit 

 varying reactivities with the same reagents and thus sug- 

 gest that the differences (in so far as they are applied 

 to the differentiation of genera) may be merely casual, 

 it will nevertheless be found perfectly clear by examina- 

 tion of the accompanying charts that the evidence in sap- 

 port of the generic and subgeneric differentiations and 

 other relations here noted is cumulative and convincing. 

 The very marked differences in the reactivities of sab- 

 generic groups which are quite as great, on the who]*-, 



